package cn.starboot.socket.utils.internal;

import java.util.Collection;
import java.util.Map;

/**
 *
 * A grab-bag of useful utility methods.
 *
 * @author netty
 * @author MDong
 */
public final class ObjUtils {
	private static final float FLOAT_ZERO = 0.0F;
	private static final double DOUBLE_ZERO = 0.0D;
	private static final long LONG_ZERO = 0L;
	private static final int INT_ZERO = 0;

	private ObjUtils() {
	}

	/**
	 * Checks that the given argument is not null. If it is, throws {@link NullPointerException}.
	 * Otherwise, returns the argument.
	 */
	public static <T> T checkNotNull(T arg, String text) {
		if (arg == null) {
			throw new NullPointerException(text);
		}
		return arg;
	}

	/**
	 * Check that the given varargs is not null and does not contain elements
	 * null elements.
	 *
	 * If it is, throws {@link NullPointerException}.
	 * Otherwise, returns the argument.
	 */
	@SafeVarargs
	public static <T> T[] deepCheckNotNull(String text, T... varargs) {
		if (varargs == null) {
			throw new NullPointerException(text);
		}

		for (T element : varargs) {
			if (element == null) {
				throw new NullPointerException(text);
			}
		}
		return varargs;
	}

	/**
	 * Checks that the given argument is not null. If it is, throws {@link IllegalArgumentException}.
	 * Otherwise, returns the argument.
	 */
	public static <T> T checkNotNullWithIAE(final T arg, final String paramName) throws IllegalArgumentException {
		if (arg == null) {
			throw new IllegalArgumentException("Param '" + paramName + "' must not be null");
		}
		return arg;
	}

	/**
	 * Checks that the given argument is not null. If it is, throws {@link IllegalArgumentException}.
	 * Otherwise, returns the argument.
	 *
	 * @param <T> type of the given argument value.
	 * @param name of the parameter, belongs to the exception message.
	 * @param index of the array, belongs to the exception message.
	 * @param value to check.
	 * @return the given argument value.
	 * @throws IllegalArgumentException if value is null.
	 */
	public static <T> T checkNotNullArrayParam(T value, int index, String name) throws IllegalArgumentException {
		if (value == null) {
			throw new IllegalArgumentException(
					"Array index " + index + " of parameter '" + name + "' must not be null");
		}
		return value;
	}

	/**
	 * Checks that the given argument is strictly positive. If it is not, throws {@link IllegalArgumentException}.
	 * Otherwise, returns the argument.
	 */
	public static int checkPositive(int i, String name) {
		if (i <= INT_ZERO) {
			throw new IllegalArgumentException(name + " : " + i + " (expected: > 0)");
		}
		return i;
	}

	/**
	 * Checks that the given argument is strictly positive. If it is not, throws {@link IllegalArgumentException}.
	 * Otherwise, returns the argument.
	 */
	public static long checkPositive(long l, String name) {
		if (l <= LONG_ZERO) {
			throw new IllegalArgumentException(name + " : " + l + " (expected: > 0)");
		}
		return l;
	}

	/**
	 * Checks that the given argument is strictly positive. If it is not, throws {@link IllegalArgumentException}.
	 * Otherwise, returns the argument.
	 */
	public static double checkPositive(final double d, final String name) {
		if (d <= DOUBLE_ZERO) {
			throw new IllegalArgumentException(name + " : " + d + " (expected: > 0)");
		}
		return d;
	}

	/**
	 * Checks that the given argument is strictly positive. If it is not, throws {@link IllegalArgumentException}.
	 * Otherwise, returns the argument.
	 */
	public static float checkPositive(final float f, final String name) {
		if (f <= FLOAT_ZERO) {
			throw new IllegalArgumentException(name + " : " + f + " (expected: > 0)");
		}
		return f;
	}

	/**
	 * Checks that the given argument is positive or zero. If it is not , throws {@link IllegalArgumentException}.
	 * Otherwise, returns the argument.
	 */
	public static int checkPositiveOrZero(int i, String name) {
		if (i < INT_ZERO) {
			throw new IllegalArgumentException(name + " : " + i + " (expected: >= 0)");
		}
		return i;
	}

	/**
	 * Checks that the given argument is positive or zero. If it is not, throws {@link IllegalArgumentException}.
	 * Otherwise, returns the argument.
	 */
	public static long checkPositiveOrZero(long l, String name) {
		if (l < LONG_ZERO) {
			throw new IllegalArgumentException(name + " : " + l + " (expected: >= 0)");
		}
		return l;
	}

	/**
	 * Checks that the given argument is positive or zero. If it is not, throws {@link IllegalArgumentException}.
	 * Otherwise, returns the argument.
	 */
	public static double checkPositiveOrZero(final double d, final String name) {
		if (d < DOUBLE_ZERO) {
			throw new IllegalArgumentException(name + " : " + d + " (expected: >= 0)");
		}
		return d;
	}

	/**
	 * Checks that the given argument is positive or zero. If it is not, throws {@link IllegalArgumentException}.
	 * Otherwise, returns the argument.
	 */
	public static float checkPositiveOrZero(final float f, final String name) {
		if (f < FLOAT_ZERO) {
			throw new IllegalArgumentException(name + " : " + f + " (expected: >= 0)");
		}
		return f;
	}

	/**
	 * Checks that the given argument is in range. If it is not, throws {@link IllegalArgumentException}.
	 * Otherwise, returns the argument.
	 */
	public static int checkInRange(int i, int start, int end, String name) {
		if (i < start || i > end) {
			throw new IllegalArgumentException(name + ": " + i + " (expected: " + start + "-" + end + ")");
		}
		return i;
	}

	/**
	 * Checks that the given argument is in range. If it is not, throws {@link IllegalArgumentException}.
	 * Otherwise, returns the argument.
	 */
	public static long checkInRange(long l, long start, long end, String name) {
		if (l < start || l > end) {
			throw new IllegalArgumentException(name + ": " + l + " (expected: " + start + "-" + end + ")");
		}
		return l;
	}

	/**
	 * Checks that the given argument is neither null nor empty.
	 * If it is, throws {@link NullPointerException} or {@link IllegalArgumentException}.
	 * Otherwise, returns the argument.
	 */
	public static <T> T[] checkNonEmpty(T[] array, String name) {
		//No String concatenation for check
		if (checkNotNull(array, name).length == 0) {
			throw new IllegalArgumentException("Param '" + name + "' must not be empty");
		}
		return array;
	}

	/**
	 * Checks that the given argument is neither null nor empty.
	 * If it is, throws {@link NullPointerException} or {@link IllegalArgumentException}.
	 * Otherwise, returns the argument.
	 */
	public static byte[] checkNonEmpty(byte[] array, String name) {
		//No String concatenation for check
		if (checkNotNull(array, name).length == 0) {
			throw new IllegalArgumentException("Param '" + name + "' must not be empty");
		}
		return array;
	}

	/**
	 * Checks that the given argument is neither null nor empty.
	 * If it is, throws {@link NullPointerException} or {@link IllegalArgumentException}.
	 * Otherwise, returns the argument.
	 */
	public static char[] checkNonEmpty(char[] array, String name) {
		//No String concatenation for check
		if (checkNotNull(array, name).length == 0) {
			throw new IllegalArgumentException("Param '" + name + "' must not be empty");
		}
		return array;
	}

	/**
	 * Checks that the given argument is neither null nor empty.
	 * If it is, throws {@link NullPointerException} or {@link IllegalArgumentException}.
	 * Otherwise, returns the argument.
	 */
	public static <T extends Collection<?>> T checkNonEmpty(T collection, String name) {
		//No String concatenation for check
		if (checkNotNull(collection, name).isEmpty()) {
			throw new IllegalArgumentException("Param '" + name + "' must not be empty");
		}
		return collection;
	}

	/**
	 * Checks that the given argument is neither null nor empty.
	 * If it is, throws {@link NullPointerException} or {@link IllegalArgumentException}.
	 * Otherwise, returns the argument.
	 */
	public static String checkNonEmpty(final String value, final String name) {
		if (checkNotNull(value, name).isEmpty()) {
			throw new IllegalArgumentException("Param '" + name + "' must not be empty");
		}
		return value;
	}

	/**
	 * Checks that the given argument is neither null nor empty.
	 * If it is, throws {@link NullPointerException} or {@link IllegalArgumentException}.
	 * Otherwise, returns the argument.
	 */
	public static <K, V, T extends Map<K, V>> T checkNonEmpty(T value, String name) {
		if (checkNotNull(value, name).isEmpty()) {
			throw new IllegalArgumentException("Param '" + name + "' must not be empty");
		}
		return value;
	}

	/**
	 * Checks that the given argument is neither null nor empty.
	 * If it is, throws {@link NullPointerException} or {@link IllegalArgumentException}.
	 * Otherwise, returns the argument.
	 */
	public static CharSequence checkNonEmpty(final CharSequence value, final String name) {
		if (checkNotNull(value, name).length() == 0) {
			throw new IllegalArgumentException("Param '" + name + "' must not be empty");
		}
		return value;
	}

	/**
	 * Trims the given argument and checks whether it is neither null nor empty.
	 * If it is, throws {@link NullPointerException} or {@link IllegalArgumentException}.
	 * Otherwise, returns the trimmed argument.
	 *
	 * @param value to trim and check.
	 * @param name of the parameter.
	 * @return the trimmed (not the original) value.
	 * @throws NullPointerException if value is null.
	 * @throws IllegalArgumentException if the trimmed value is empty.
	 */
	public static String checkNonEmptyAfterTrim(final String value, final String name) {
		String trimmed = checkNotNull(value, name).trim();
		return checkNonEmpty(trimmed, name);
	}

	/**
	 * Resolves a possibly null Integer to a primitive int, using a default value.
	 * @param wrapper the wrapper
	 * @param defaultValue the default value
	 * @return the primitive value
	 */
	public static int intValue(Integer wrapper, int defaultValue) {
		return wrapper != null ? wrapper : defaultValue;
	}

	/**
	 * Resolves a possibly null Long to a primitive long, using a default value.
	 * @param wrapper the wrapper
	 * @param defaultValue the default value
	 * @return the primitive value
	 */
	public static long longValue(Long wrapper, long defaultValue) {
		return wrapper != null ? wrapper : defaultValue;
	}
}
